The G7 countries and Australia have agreed that the price ceiling for Russian oil will be set at a certain fixed level without using a floating rate, sources familiar with the talks said Thursday.

Representatives of the G-7 countries have been in intensive negotiations in recent weeks over an unprecedented plan to cap prices for offshore supplies of Russian oil, which is due to go into effect Dec. 5. It would help enforce the sanctions regime imposed by EU countries and the U.S. to limit Moscow's ability to finance the invasion of Ukraine.

The coalition has agreed that the price ceiling will be expressed as a fixed price that will be reviewed regularly, said a coalition source not authorized to speak publicly.

This will increase market stability and simplify compliance to minimize the burden on market participants, he added.

The price has not yet been set, but should be announced in the coming weeks, several sources said. Coalition partners have agreed to regularly review the fixed price as needed, the source said, without disclosing details.

Tying the price to any index would lead to too much volatility and possible price fluctuations, the source added.

The coalition is concerned that a floating price below the international Brent oil benchmark could allow Russian President Vladimir Putin to cheat the mechanism by cutting supply, said a second source familiar with the discussions.

Putin could benefit from a system of floating prices because the price of Russian oil would also rise if Brent crude were to rise in price because of cuts in oil supplies from Russia, one of the world's largest oil producers. According to the source, the disadvantage of a negotiated system of fixed prices is that it would require more coalition meetings to be reviewed regularly.

U.S. Treasury Secretary Janet Yellen and other G7 officials say the price caps, which are due to begin on Dec. 5 for oil and Feb. 5 for oil products, would cut Russian profits without cutting supplies to consumers. Russia has said it will refuse to supply oil to countries that impose a price ceiling.

A permanent price ceiling could allow insurers to more confidently renew contracts and enter into new ones without fear that the price might be adjusted by countries buying Russian oil, potentially exposing insurers to sanctions.